Heat storage unit

ABSTRACT

A heat storage unit capable of efficiently storing heat in a short time. The unit includes: a heat storage container  1   a  that houses sodium acetate  3,  which stores heat by a state change between solid and liquid, and oil  2,  which exchanges heat by directly contacting the sodium acetate  3,  has smaller specific gravity than that of the sodium acetate  3,  and is separated from the sodium acetate  3.  Further, the unit includes: a supply pipe  4  that passes at least through the sodium acetate  3  housed in the heat storage container  1   a  and supplies the oil  2  into the heat storage container  1   a;  and a discharge pipe that discharges the oil  2  housed in the heat storage container  1   a  to the outside of the heat storage container  1   a.  Then, the supply pipe  4  crosses the boundary surface between the oil  2  and the sodium acetate  3  which are housed in the heat storage container  1   a,  has a plurality of discharge holes that discharge the supplied oil  2   a,  and at least one of the discharge holes  6  are positioned in the oil  2.

TECHNICAL FIELD

The present invention relates to a heat storage unit capable of storinggenerated heat and transporting the heat to a remote place.

BACKGROUND ART

Heat generated from a factory such as an ironworks and garbage-disposalfacility, for example, is used in various kinds of facility near thefactory. Further, by temporarily storing the heat generated from thefactory in a heat storage body or the like and by transporting the heatstorage body, the heat can be used in the remote place from the factory.As a device for storing heat, there exists a device that performs heatexchange by allowing a medium such as oil, to which heat is supplied, todirectly contact metal hydrate and stores heat in the metal hydrate.

For example, the heat storage body such as sodium acetate and oil havinga smaller specific gravity than that of the heat storage body are housedin the storage container of Patent Document 1. Since the specificgravity of oil is smaller and the oil and the heat storage body do notmix, they are housed vertically in a separated manner. Then, pipes aredisposed in the oil and the heat storage body, and they are severallyconnected to a heat exchanger. The oil is taken into the heat exchangerfrom one pipe to supply heat, and the oil to which heat was supplied isdischarged from the other pipe into the heat storage body. Since thedischarged oil has a small specific gravity, it goes up to the oil inthe upper area. Heat is exchanged by the direct contact between the heatstorage body and the oil while the oil goes up. By repeating theabove-described action, heat is stored in the heat storage body. Then,the pipes of Patent Document 1 are in a double pipe structure in orderto prevent impurities from being mixed into the pipes or the heatexchanger.

Patent Document 1: International Publication No. WO 03/019099 (FIG. 1)

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

The heat storage body such as sodium acetate that stores heat utilizeslatent heat of fusion, where the state of the heat storage body changesfrom solid to liquid as heat is added, and heat is thus stored.Therefore, in Patent Document 1, the heat storage body is solid at thestarting point of heat supply, so that discharge holes are clogged up bysolid heat storage body even when the oil to which heat was supplied isready to be discharged from the pipe arranged inside the heat storagebody, the oil cannot be discharged until heat is applied to the heatstorage body to change its state to liquid, and heat cannot be suppliedto the heat storage body. As a result, enormous time is spent in storingheat.

Consequently, it is an object of the present invention to provide a heatstorage unit capable of storing heat efficiently in a short time.

Means for Solving the Problems and Effects

The present invention includes: a storage container that houses a heatstorage body, which stores heat by a state change from solid to liquid,and a heat exchange medium, which exchanges heat by directly contactingthe heat storage body, has a smaller specific gravity than that of theheat storage body, and is separated from the heat storage body; a supplypipe that passes through at least the heat storage body housed in thestorage container and supplies the heat exchange medium into the storagecontainer; and a discharge pipe that discharges the heat exchange mediumhoused in the storage container to the outside of the storage container,in which the supply pipe crosses a boundary surface between the heatexchange medium and the heat storage body, has a plurality of dischargeholes that discharge the supplied heat exchange medium, and at least oneof the discharge holes is positioned inside the heat exchange medium.

With this constitution, the heat exchange medium can be discharged fromthe supply pipe regardless of the state of the heat storage body becausethe discharge holes are provided in the heat exchange medium side. Theheat storage body is solid under normal state and changes to liquid asheat is stored. For this reason, the discharge holes are clogged up bythe solid heat storage body at the starting point of heat supply even ifthe discharge holes are provided for the supply pipe arranged in theheat storage body. Then, the supplied heat exchange medium can bedischarged by providing the discharge holes on the heat exchange mediumside, and heat can be conducted to the heat storage body. Then, once theheat storage body changes from solid to liquid, the heat exchange mediumcan be discharged from the discharge holes provided on the heat storagebody side as well. This makes it possible to contact the heat storagebody and the heat exchange medium in a short time, so that a heatstorage time can be shortened. Further, when the discharge holes are notprovided in the heat exchange medium, there is a possibility that thedischarge holes provided on the heat storage body side are clogged up,the heat exchange medium passing through the supply pipe is notdischarged and heat cannot be stored, but such danger can be eliminated.

It is preferable that the supply pipe of the present invention crossvertically with respect to the boundary surface. With this, the heatexchange medium can be discharged along the supply pipe by allowing thesupply pipe to cross vertically the boundary surface, and heat can bestored in the heat storage body near the supply pipe first. Thus, heatexchange from the heat exchange medium to the heat storage body can beperformed efficiently.

In this case, it is preferable that the supply pipe be disposedcoaxially around the circumference of an area having the discharge holesand have a circulation pipe to allow the heat exchange medium dischargedfrom the discharge holes to go up in the vertical direction. With thisconstitution, by allowing the supplied heat exchange medium to bedischarged in the vertical direction along the circulation pipe,circulating flow associated with temperature change occurs around thecirculation pipe. With this, heat can be conducted efficiently to theheat storage body and a heat storage time can be shortened.

In another aspect, the present invention includes: a storage containerthat houses a heat storage body, which stores heat by a state changefrom solid to liquid, and a heat exchange medium, which exchanges heatby directly contacting the heat storage body, has a smaller specificgravity than that of the heat storage body, and is separated from theheat storage body; a supply pipe that passes through at least the heatstorage body housed in the storage container and supplies the heatexchange medium into the storage container; and a discharge pipe thatdischarges the heat exchange medium housed in the storage container tothe outside of the storage container, in which the supply pipe includesa first supply pipe having discharge holes that discharge the suppliedheat exchange medium into the heat storage body and a second supply pipethat crosses the boundary surface between the heat exchange medium andthe heat storage body, which are housed in the storage container, andhas an outlet inside the heat exchange medium.

With this constitution, heat storage time can be shortened by usingfirst and second flow pipes. The heat storage body can store heat bychanging its state from solid to liquid. Therefore, since the heatstorage body is solid at the starting point of heat storage, thedischarge holes provided for the first supply pipe are clogged up andthey cannot discharge the supplied heat exchange medium. On the otherhand, since the second supply pipe has an outlet in the heat exchangemedium, it can constantly discharge the supplied heat exchange medium.For this reason, heat can be conducted by indirect contact of the heatexchange medium flowing in the second supply pipe to change the heatstorage body from solid to liquid. Then, by changing the heat storagebody to liquid, the heat exchange medium can be discharged from thedischarge holes of the first supply pipe. By switching the two supplypipes to store heat in the heat storage body in this manner, heatstorage time can be shortened.

It is preferable for the present invention that, in the heat storagebody, the second supply pipe surround at least a part of the firstsupply pipe including the discharge holes and have a communicatingportion that guides the discharge holes to the heat exchange medium.With this, when the second supply pipe is surrounded by the first supplypipe, the periphery of the second supply pipe and the periphery of thedischarge holes for heat exchange medium of the first supply pipe can beheated by the heat exchange medium flowing in the second supply pipe. Byquickly heating these areas to melt the solid heat storage body, theheat exchange medium is quickly discharged from the first supply pipe toallow the heat storage body to directly contact the heat exchangemedium, and the heat storage time can be shortened.

It is preferable for the present invention that a switching valve forswitching supply and cutoff of the heat exchange medium depending on thestate of the heat storage body be provided severally for the first andsecond supply pipes. With this constitution, timing for switching thesupply pipes can be changed depending on the state of the heat storagebody, and heat can be stored more efficiently. For example, the pipescan be switched such that the heat exchange medium is supplied to bothof the first supply pipe and the second supply pipe at the startingpoint of heat storage and then the medium is supplied only to the firstsupply pipe, and thus heat can be stored efficiently.

In the case where the supply pipe or at least a part of the first supplypipe extends in the horizontal direction, the present invention may beprovided with the discharge holes for an area extending in thehorizontal direction such that the holes are open in the verticallydownward direction. With this, the specific gravity of the heat exchangemedium is smaller than that of the heat storage body, so that a dangerthat the heat storage body enters inside the supply pipe from thedischarge holes is eliminated when the discharge holes are opendownward.

It is preferable for the present invention that, in the heat storagebody, the supply pipe or the first supply pipe have an expanded portionthat is in a shape that widens toward the end and provided with thedischarge holes on the bottom surface. With this constitution, thespecific gravity of the heat exchange medium is smaller than that of theheat storage body, so that a danger that the heat storage body entersinside the supply pipe from the discharge holes is eliminated becausethe discharge holes are open downward. Furthermore, more heat exchangemedium can be discharged by forming the pipe in the shape that widenstoward the end, and the heat storage time can be shortened.

Further, in another aspect, the present invention includes: a storagecontainer that houses a heat storage body, which stores heat by a statechange from solid to liquid, and a heat exchange medium, which exchangesheat by directly contacting the heat storage body, has a smallerspecific gravity than that of the heat storage body, and is separatedfrom the heat storage body; a supply pipe that passes through at leastthe heat storage body housed in the storage container and supplies theheat exchange medium into the storage container; and a discharge pipethat discharges the heat exchange medium -housed in the storagecontainer to the outside of the storage container, in which the supplypipe includes a first supply pipe having an outlet that discharges thesupplied heat exchange medium into the housed heat storage body and asecond supply pipe that has at least a part of the first supply pipeinside thereof and has discharge holes that discharge the supplied heatexchange medium into the heat storage body.

With this constitution, the heat exchange medium can constantly flow inthe first supply pipe regardless of the state of heat storage body, sothat heat can be conducted to the heat exchange medium in the secondsupply pipe and high temperature can be maintained. Thus, hightemperature can be discharged from the discharge holes, so that heat canbe sufficiently stored.

It is preferable that the present invention, in the case where thesupply pipes are provided parallelly in the heat storage body, beprovided with a thermal conduction member for conducting heat of thesupply pipes to the heat storage body between the supply pipes. Withthis, heat can be supplied to the heat storage body in a shorter time,and the heat storage time can be shortened.

It is preferable that at least a part of the supply pipe of the presentinvention be provided on the bottom surface of the storage container.With this constitution, the heat exchange medium to be discharged goesup because its specific gravity is lighter than the heat storage body,and a contact time between the discharged heat exchange medium and theheat storage body can be made longer by providing the supply pipe on thebottom surface. Further, in the present invention, it is preferable thatthe second supply pipe be provided on the bottom surface of the storagecontainer so as to cover the bottom surface. With this, a contactsurface between the second supply pipe and the heat storage body is wideand heat can be stored from the bottom portion of the heat storage body,so that the heat storage time can be shortened.

It is preferable that the connection port of the supply pipe of thepresent invention be positioned above the connection port of thedischarge pipe. With this constitution, by allowing the connection portof the supply pipe to be positioned higher than the connection port ofthe discharge pipe, the heat exchange medium from the discharge pipe canbe inversely flown first when the heat storage body or the heat exchangemedium flows inversely, and it is possible to avoid a danger that theheat storage body to which heat is stored flows inversely.

It is preferable that the present invention have wave-absorbing platesthat are parallelly arranged with each other along the boundary surfacebetween the heat storage body and the heat exchange medium, arrangedvertically with respect to the boundary surface, and prevent agitationon the boundary surface. With this constitution, it is possible toprevent agitation on the boundary surface caused by vibration associatedwith transportation in the heat storage state.

It is preferable that the discharge pipe of the present inventioninclude a separation mechanism that separates the heat storage body andthe heat exchange medium. With this constitution, the heat storage bodycan be removed if it is mixed in the heat exchange medium to bedischarged outside the storage container. In this case, it is preferablethat the separation mechanism have a separator for allowing the heatexchange medium and the heat storage body, which were taken in, to flowhorizontally in one direction and a discharge hole that discharges theheat storage body, which is being precipitated, from the separator, andthe separator have a shape for guiding the precipitated heat storagebody toward the discharge hole. With this, the heat storage body and theheat exchange medium can be separated with a simple structure.

Furthermore, it is preferable that the heat storage body of the presentinvention be erythritol. With this, it is possible to store heatefficiently in a short time.

Best Mode for Implementing the Invention

In the following, description will be made for the preferred embodimentsof the present invention with reference to the drawings.

(First Embodiment)

A heat storage unit 1 according to the first embodiment of the presentinvention is preferably used in a portable heat storage unit. Forexample, as shown in FIG. 1, it is applied for a heat transportationsystem that transports heat when a factory 60 generating heat andfacility 70 using the heat are remote from each other. The heat storageunit 1 is detachable to connection ports 51, 52 of heat exchangers 5 a,5 b that store heat or discharge heat to/from the heat storage unit 1,and is transported between the factory 60 and the facility 70 by avehicle 50 such as a truck. The factory 60 is a garbage-incineratingfacility, a power generating plant, an ironworks or the like, and heatgenerated in the factory is stored in the heat storage unit 1 via theheat exchanger 5 a. Further, the facility 70 is facility such as aheated swimming pool and a hospital, and the heat stored in the heatstorage unit 1 is applied for temperature-control system or the like inthe facility via the heat exchanger 5 b. In the following description,heat exchange in the factory 60 side will be explained.

The heat storage unit 1 includes a heat storage container 1 a (storagecontainer) that houses oil 2 (heat exchange medium) and sodium acetatetrihydrate salt 3 (heat storage body) (hereinafter, referred to assodium acetate 3), a supply pipe 4, and a discharge pipe 6. Since theoil 2 and the sodium acetate 3 are not mixed with each other and the oil2 has a smaller specific gravity than that of the sodium acetate 3, theoil 2 and the sodium acetate 3 are housed in the heat storage container1 a severally in an upper layer and a lower layer in a separate manner.Furthermore, since the oil 2 and the sodium acetate 3 are not mixed,that is, the oil 2 and the sodium acetate 3 are separate from eachother, a member or the like for separating the oil 2 from the sodiumacetate 3 is not laid between them and the oil 2 is in directly contactwith the sodium acetate 3.

The oil 2 performs heat exchange with the sodium acetate 3 by directcontact with the sodium acetate 3. The oil 2, when it is taken into theheat exchanger 5 a from the discharge pipe 6 (described later) and heatis supplied in the heat exchanger 5 a (in the description below, the oil2 to which heat was supplied in the heat exchanger 5 a will be calledoil 2 a), it is discharged into the sodium acetate 3 via the supply pipe4. Since the discharged oil 2 a has a smaller specific gravity than thatof the sodium acetate 3, it goes up to the oil 2 of the upper layer andis taken in by the oil 2. During the upward movement, the heat suppliedto the oil 2 a is conducted to the sodium acetate 3 due to the directcontact with the sodium acetate 3.

The sodium acetate 3 stores the heat conducted from the above-describedoil 2 a. The melting point of the sodium acetate 3 is about 58° C. andit is solid under the normal state (room temperature). Then, its statechanges from solid to liquid when the heat is conducted from the oil 2 adue to the direct contact, and heat is stored during a liquid state.

The supply pipe 4 is provided in the upper layer portion of the heatstorage container 1 a, where the housed oil 2 is positioned, in apenetrated manner, and a connection port 41 is detachably connected tothe connection port 51 of the heat exchanger 5 a. The supply pipe 4 thatis provided for the heat storage container 1 a in a penetrated mannervertically crosses the boundary surface between the oil 2 and the sodiumacetate 3 and enters the sodium acetate 3, and furthermore, it is bentin an L-shape and horizontally extended. The supply pipe 4 has aninternal space and the oil 2 a to which heat was supplied by the heatexchanger 5 a flows in the internal space.

Further, the supply pipe 4 has a plurality of discharge holes 4 a, 4 b,which discharge the oil 2 a flowing inside the pipe, along its axisdirection. A plurality of discharge holes 4 a are provided above aboundary surface while using the boundary surface between the oil 2 andthe sodium acetate 3 as a boundary, that is, on the supply pipe 4 of theoil 2 side. Furthermore, one or more discharge holes 4 b are providedbelow the boundary surface, that is, on the supply pipe 4 of the sodiumacetate 3 side. Note that the discharge holes 4 b provided in an areawhere the supply pipe 4 is bent in an L-shape and horizontally extended,are provided so as to be open vertically downward. Thus, since thesodium acetate 3 has a larger specific gravity than that of the oil 2 a,the sodium acetate 3 does not enter the supply pipe 4 while pushingaside the oil 2 a to be discharged from the discharge holes 4 b, andthis prevents the sodium acetate 3 from being solidified and cloggedinside the supply pipe 4.

The discharge pipe 6 is provided in the upper layer portion of the heatstorage container 1 a, where the housed oil 2 is positioned, in apenetrated manner. Then, a connection port 61 of the discharge pipe 6 isdetachably connected to the connection port 52 of the heat exchanger 5 ato take the oil 2 inside the heat storage container 1 a into the heatexchanger 5 a. At this point, the connection port 61 of the dischargepipe 6 is disposed on the heat storage container 1 a so as to be belowthe connection port 41 of the supply pipe 4, that is, such that thedischarge pipe 6 is below the supply pipe 4. If the supply pipe 4 andthe discharge pipe 6 are removed from the heat exchanger 5 a in a wrongprocedure, there is a possibility that the oil 2 or the sodium acetate 3flows inversely due to a pressure difference between the outside and theinside of the heat storage container 1 a. For this reason, the dischargepipe 6 is arranged below the supply pipe 4 to allow the oil 2 to whichheat is not applied to flow inversely first from the discharge pipe 6.Consequently, a pressure difference from the outside is eliminated and adanger that the sodium acetate 3 to which heat is stored flows inverselyfrom the supply pipe 4 is prevented.

The heat exchanger 5 a stores heat generated from the factory 60 in theheat storage container 1 a. As described above, the supply pipe 4 andthe discharge pipe 6 are connected detachably to the heat exchanger 5 a.Then, the supply pipe 4 and the discharge pipe 6 are communicated witheach other in the heat exchanger 5 a. Moreover, a pipe (not shown) thattakes in the heat generated from the factory 60 as steam and a pipe(also not shown) that discharges steam from which heat has been removedare connected to the heat exchanger 5 a, and the pipes are communicatedwith each other in the heat exchanger 5 a via a pipe arranged so as tosurround the communicated portion between the supply pipe 4 and thedischarge pipe 6. Further, a pump (not shown) is disposed for theconnection port 51 of the heat exchanger 5 a, and it takes the oil 2into the heat exchanger 5 a and sends the oil 2 that was taken in to theheat storage container 1 a.

The heat exchanger 5 a takes in the oil 2 inside heat storage container1 a by the pump via the discharge pipe 6 while it takes in steamgenerated from the factory 60 via the pipe. The steam that was taken inconducts heat to the oil 2, which was taken in, by indirect contact ofthe pipes in the communicated portion between the supply pipe 4 and thedischarge pipe 6. After that, the oil 2 a to which heat was supplied issupplied into the heat storage container 1 a via the supply pipe 4. Inaddition, the steam from which heat was removed is discharged via thepipe. When the heat exchanger 5 a repeats the above-described action,the heat generated from the factory 60 can be stored in the sodiumacetate 3 of the heat storage unit 1.

Next, description will be made for the heat storage method to the heatstorage unit 1.

The steam generated from the factory 60 is taken into the heat exchanger5 a. On the other hand, the oil 2 inside the heat storage container 1 ais taken into the heat exchanger 5 a via the discharge pipe 6. Then, inthe heat exchanger 5 a, heat of the steam is conducted to the oil 2 thatwas taken in. The oil 2 a to which heat was supplied is returned to theheat storage container 1 a via the supply pipe 4.

The oil 2 a flows in the supply pipe 4 and is discharged from thedischarge holes 4 a, 4 b. Since the sodium acetate 3 at the startingpoint of heat storage is solid and the discharge holes 4 b are providedin the sodium acetate 3 side, the discharge holes 4 b is in the state ofbeing clogged by the solid sodium acetate 3. For this reason, the oil 2a is not discharged from the discharge holes 4 b.

On the other hand, since the discharge holes 4 a are provided in the oil2 side, the oil 2 a can be discharged without clogging the dischargeholes 4 a. Then, the oil 2 a discharged from the discharge holes 4 aconducts heat to the sodium acetate 3 near the boundary surface betweenthe oil 2 and the sodium acetate 3. With this, the state of the sodiumacetate 3 gradually changes from solid to liquid from the upper portionthereof, and the oil 2 a is discharged from the discharge holes 4 b aswell. Due to the direct contact with the discharged oil 2 a, heat isstored in the sodium acetate 3. Furthermore, the oil 2 a flowing in thesupply pipe 4 conducts heat to the sodium acetate 3 via the supply pipe4 due to the indirect contact. This makes it possible to change thesodium acetate 3 from solid to liquid even faster and the heat storagetime can be shortened.

When the sodium acetate 3 becomes a liquid state and the oil 2 a isdischarged into the sodium acetate 3, it goes up to the oil 2 in theupper layer and is taken into the layer because the specific gravity ofthe oil 2 a is smaller than that of the sodium acetate 3. The oil 2 aconducts heat to the sodium acetate 3 as it goes up. By repeating theabove-described action, heat can be stored in the sodium acetate 3.

Meanwhile, description has been made for the heat exchange in thefactory 60 side, but the same applies to the heat exchange in thefacility 70 side. Specifically, the sodium acetate 3 is liquid in thestate where heat was supplied, and stored heat can be taken out from theliquid. The supply pipe 4 and the discharge pipe 6 of the heat storageunit 1 are connected detachably to the heat exchanger 5 b that takes outthe heat stored in the heat storage unit 1, and furthermore, a pipe fortaking in gas or liquid and a pipe for supplying to heated gas or liquidand for supplying to the temperature-control system of the facility 70are connected to the heat exchanger 5 b.

The heat exchanger 5 b discharges the oil 2 into the sodium acetate 3 inwhich heat is stored via the supply pipe 4. Heat is conducted from thesodium acetate 3 to the discharged oil 2 due to the direct contact as itgoes up. With this, heat is supplied to the oil 2 in the upper layer andthe oil is taken into the heat exchanger 5 b from the discharge pipe 6.On the other hand, gas or liquid such as water is taken into the heatexchanger 5 b. Then, heat is conducted from the oil 2 to which heat wasapplied to gas or liquid. The gas or liquid to which heat was conductedpasses through the pipe and is supplied to the temperature-controlsystem in the facility 70. By repeating the above-described action, heatstored in the sodium acetate 3 can be taken out.

Next, description will be made for a heat transportation system usingthe heat storage unit 1 according to the first embodiment. By repeatingthe above-described action, the heat generated from the factory 60 dueto garbage incineration or the like is stored in the heat storage unit1. Since the heat storage unit 1 is connected to the heat exchanger 5 adetachably, it is removed after heat storage is completed, andtransported to the facility 70 requiring the stored heat by the vehicle50 such as a truck. The transported heat storage unit 1 is connected tothe heat exchanger 5 b, the heat stored in the heat storage unit 1 istaken out, and used in the temperature-control system or the like of thefacility 70.

As described above, because the discharge holes 4 a are provided in theoil 2 side of the supply pipe 4 in this embodiment, even if the sodiumacetate 3 is solid at the starting point of heat storage, the solidsodium acetate 3 can be changed to liquid in a shorter time bydischarging the oil 2 a from the discharge holes 4 a. With this, theheat storage time to the sodium acetate 3 can be shortened.

Furthermore, by allowing the supply pipe 4 to vertically cross theboundary surface between the oil 2 and the sodium acetate 3, the sodiumacetate 3 near the supply pipe 4 can be changed from solid to a liquidstate by the oil 2 a discharged from the discharge holes 4 a, and thusthe oil 2 a can be discharged faster from the discharge holes 4 b.Consequently, the heat storage time can be even shorter.

Meanwhile, as a modified example of this embodiment, a circulation pipe4 c may be provided as shown in FIG. 3. The circulation pipe 4 c isprovided so as to surround the circumference of the supply pipe 4 thatvertically crosses boundary surface between the oil 2 and the sodiumacetate 3, and serves as a guide for allowing the oil 2 a, which isdischarged from the discharge holes 4 b, to go up in the verticaldirection after the state of the sodium acetate 3 is changed to liquid.When the oil 2 a to which heat was supplied, which is discharged fromthe discharge holes 4 b, goes up along the circulation pipe 4 c, theliquid sodium acetate 3 having low temperature moves toward the bottomportion of the circulation pipe 4 c, and circulating flow is generatedaround the circulation pipe 4 c as shown by the arrows in the drawing.This allows heat to circulate, and an effect is exerted that the heatstorage time is shortened by efficiently storing heat in the sodiumacetate 3.

Further, as another modified example of this embodiment, a plurality ofplates 11 (wave-absorbing plates) may be provided so as to verticallycross the boundary surface between the oil 2 and the sodium acetate 3 asshown in FIG. 4. By providing the plates 11, the oil 2 and the sodiumacetate 3 vibrate during the transportation of the heat storage unit 1to generate waves, and agitation on the boundary surface can beprevented. By preventing agitation, heat stored in the sodium acetate 3can be held.

Furthermore, as another modified example, a separation device 12 may beprovided halfway the discharge pipe 6. The separating device 12 is adevice that separates the oil 2 and the sodium acetate 3 when the sodiumacetate 3 is mixed in the oil 2 that was taken in. For example, althoughnot shown, the separation device 12 has a structure where it takes outthe oil 2, which was taken in, from the upper portion of the separationdevice 12 while it spirally rotates the oil 2 that was taken in. In thiscase, since the sodium acetate 3 has a larger specific gravity than thatof the oil 2, the sodium acetate 3 is discharged from an outlet at thebottom portion of the separation device 12 along the sidewall surface ofthe separation device 12 when it hits the sidewall surface due tocentrifugal force, and only the oil 2 is taken into the heat exchanger 5a. With this, the sodium acetate 3 can be removed from the oil 2 to betaken into the heat exchanger 5 a, and a danger of a failure or the likethat is caused when the sodium acetate 3 enters the heat exchanger 5 ais eliminated. The above-described modified examples can be applied forembodiments described below.

Meanwhile, the supply pipe 4 vertically crosses the boundary surfacebetween the oil 2 and the sodium acetate 3 in this embodiment describedabove, but it may cross the boundary surface diagonally instead ofvertically. Further, the supply pipe 4 is bent in the L-shape andextended in the horizontal direction, but it may not be extended in thehorizontal direction. The pipe may be any shape as long as it candischarge the oil 2 in the sodium acetate 3. Moreover, the side surfacemay be a shape that widens toward the end as shown in FIG. 6, or asupply portion 13 (expanded portion) having the shape that widens towardthe end may be provided halfway the supply pipe 4. In this case, it maybe a conical shape or may be hemispherical shape. Further, in this case,by providing discharge holes 13 a at the bottom surface portion, adanger that the sodium acetate 3 enters inside the pipe is eliminated.

Furthermore, in this embodiment, the discharge holes 4 b, which areprovided in the horizontally extended portion of the supply pipe 4 inthe sodium acetate 3, are provided on the lower portion of the supplypipe 4, but they may be provided on the upper portion thereof. Inaddition, in this embodiment, sodium acetate is used as a substance forstoring heat and oil is used as a substance for conducting heat, but thesubstances are not limited to them. For example, the heat storage bodymay be erythritol. Since erythritol can be heated by oil having thetemperature of 120° C. or higher, it exerts an effect that heat can bestored efficiently in a short time.

(Second Embodiment)

Next, description will be made for the heat storage unit according tothe second embodiment of the present invention. The heat storage unitaccording to this embodiment is different from the first embodiment onthe point that it is provided with two supply pipes. In the following,only the different point will be described. Note that the same referencenumerals are applied to the same members as those of the firstembodiment, and their explanation will be omitted.

As shown in FIG. 7, the heat storage unit 1 according to this embodimentis provided with a first supply pipe 7 (first supply pipe) and a secondsupply pipe 8 (second supply pipe). The first supply pipe 7 and thesecond supply pipe 8 are provided in the upper layer portion of the heatstorage container 1 a, where the housed oil 2 is positioned, in apenetrated manner, and is detachably connected to the heat exchanger 5a. Specifically, the connection port of one supply pipe 11 is detachablyconnected to the connection port 51 of the heat exchanger 5 a, and thesupply pipe 11 branches into the first supply pipe 7 and the secondsupply pipe 8. The first supply pipe 7 and the second supply pipe 8,which are provided for the heat storage container 1 a in a penetratedmanner, vertically cross the boundary surface between the oil 2 and thesodium acetate 3 and go into the sodium acetate 3, and furthermore, isbent in the L-shape and extended horizontally. Moreover, the secondsupply pipe 8 vertically crosses the boundary surface between the oil 2and the sodium acetate 3 from the end portion of the horizontallyextended portion. The first supply pipe 7 and the second supply pipe 8have an internal space, and the oil 2 a to which heat was supplied bythe heat exchanger 5 a flows in the internal space.

The first supply pipe 7 has a plurality of discharge holes 7 a thatdischarge the supplied oil 2 a into the sodium acetate 3 along the axisdirection thereof. Further, the second supply pipe 8 has outlets 8 athat discharge the supplied oil 2 a into the oil 2. The outlets 8 a areprovided on the terminal portion of the second supply pipe 8, the oil 2a supplied from the heat exchanger 5 a flows in the second supply pipe8, and is discharged into the oil 2 from the outlets 7 a. The dischargeholes 4 b provided on the portion of the first supply pipe 7, which isextended in the horizontal direction, are provided in the verticallydownward direction. Note that the first supply pipe 7 may have dischargeholes on the oil 2 side similar to the first embodiment.

As described above, the supply pipe 11 is detachably connected to theheat exchanger 5 a, and is separated into the first supply pipe 7 andthe second supply pipe 8. Then, valves 9 a, 9 b (switching valves) aredisposed severally on the first supply pipe 7 and the second supply pipe8. By opening/closing the valves 9 a, 9 b, supply and cutoff of the oil2 a to the first supply pipe 7 and the second supply pipe 8 can beswitched.

The valves 9 a, 9 b open/close depending on the state of the sodiumacetate 3. Specifically, when the sodium acetate 3 is solid, the valve 9b is closed to prevent the oil 2 a from being supplied to the secondsupply pipe 8 in order to supply the oil 2 a only to the first supplypipe 7. Further, when the sodium acetate 3 is liquid, the valve 9 a isclosed and the valve 9 b is opened to allow the oil 2 a to be suppliedonly to the second supply pipe 8. The valves 9 a, 9 b may be manuallyopened/closed by an operator, or a controller may be connected toautomatically open/close the valves. Note that description of the othermembers will be omitted because they are the same as the firstembodiment.

Next, description will be made for the heat storage method to the heatstorage unit 1.

Steam passes through the pipe from the factory 60 and is taken into theheat exchanger 5 a. On the other hand, the oil 2 in the heat storagecontainer 1 a is taken into the heat exchanger 5 a via the dischargepipe 6. Then, in the heat exchanger 5 a, heat of the steam is suppliedto the oil 2 by thermal conduction. At the starting point of heatstorage, only the valve 9 b is opened to allow the oil 2 a to besupplied only to the second supply pipe 8, and the oil 2 a to which heatwas supplied flows in the second supply pipe 8. The oil 2 a flows in thesecond supply pipe 8 and is discharged from the outlets 8 a into the oil2. The oil 2 a flowing through the second supply pipe 8 conducts heat tothe sodium acetate 3 due to indirect contact via the second supply pipe8, and thus the solid sodium acetate 3 changes into liquid.

When the sodium acetate 3 becomes approximately liquid, the valve 9 b isclosed and the valve 9 a is opened to cutoff the second supply pipe 8,and the oil 2 a is supplied to the first supply pipe 7. The oil 2 asupplied to the first supply pipe 7 flows through the first supply pipe7 and is discharged into the sodium acetate 3 from the discharge holes 7a. When the oil 2 a is discharged, it goes up to the oil 2 in the upperlayer and taken into the oil. Heat is conducted to the sodium acetate 3during the upward movement due to the direct contact with the sodiumacetate 3. With this, heat can be stored in the sodium acetate 3.

As described above, in this embodiment, by using two supply pipes forsupplying the oil 2 a to which heat was supplied, which are the firstsupply pipe 7 and the second supply pipe 8, and switching the pipesdepending on the state of the sodium acetate 3, heat can be efficientlystore in the sodium acetate 3. Since the sodium acetate 3 is solid atthe starting point of heat storage, the oil 2 a is not discharged fromthe discharge holes provided in the sodium acetate 3. For this reason,the oil 2 a is supplied to the second supply pipe 8 when the sodiumacetate 3 is solid to conduct heat to the sodium acetate 3 by indirectcontact, the oil 2 a is supplied to the first supply pipe 7 anddischarged when the sodium acetate 3 becomes liquid to conduct heat tothe sodium acetate 3 by direct contact, and thus heat can be efficientlystored in the sodium acetate 3.

Furthermore, there is a possibility that the first supply pipe 7 couldburst because the supplied oil 2 a is not discharged from the dischargeholes 7 a at the starting point of heat storage. For this reason, burstof the first supply pipe 7 can be prevented by switching the firstsupply pipe 7 and the second supply pipe 8, and the heat storage unit 1can be used safely.

Meanwhile, in this embodiment, the oil 2 is supplied either one of thefirst supply pipe 7 and the second supply pipe 8 depending on the stateof the sodium acetate 3, but the invention is not limited to this. Forexample, the oil 2 a may be supplied to only the second supply pipe 8 atthe starting point of heat storage, and after that, the oil 2 a may besupplied to both of the first supply pipe 7 and the second supply pipe8. Further, although the first supply pipe 7 a does not have dischargeholes in the above-described embodiment, the pipe may have the dischargeholes. Furthermore, supply pipes may not have the valves 9 a, 9 b.

(Third Embodiment)

Next, description will be made for the heat storage unit according tothe third embodiment of the present invention. The heat storage unitaccording to this embodiment is the same as the second embodiment on thepoint that it is provided with two supply pipes but is different on thepoint that one supply pipe surrounds the other supply pipe. In thefollowing, only the different point will be described. Note that thesame reference numerals are applied to the same members as those of thefirst and the second embodiments, and their explanation will be omitted.

As shown in FIG. 8, the heat storage unit 1 according to this embodimenthas two pipes that are the first supply pipe 7 and a second supply pipe10. The first supply pipe 7 and the second supply pipe 10 are providedin the upper layer portion of the heat storage container 1 a in apenetrated manner, where the housed oil 2 is positioned, and isdetachably connected to the heat exchanger 5 a. Specifically, theconnection port of one supply pipe 11 is detachably connected to theconnection port 51 of the heat exchanger 5 a, and the supply pipe 11branches into the first supply pipe 7 and the second supply pipe 10.Then, the first supply pipe 7 is arranged in the heat storage container1 a so as to surround the second supply pipe 10. The first supply pipe 7and the second supply pipe 10 vertically cross the boundary surfacebetween the oil 2 and the sodium acetate 3 and go into the sodiumacetate 3, and furthermore, are bent in the L-shape and extendedhorizontally. The first supply pipe 7 and the second supply pipe 10 havean internal space, and the oil 2 a to which heat was supplied by theheat exchanger 5 a flows in the internal space. As described above, thefirst supply pipe 7 is arranged in the internal space of the secondsupply pipe 10.

In the horizontally extended portion of the second supply pipe 10, aplurality of supply tubes 10 a, which vertically cross the boundarysurface between the oil 2 and the sodium acetate 3, are disposed. Thesupply tubes 10 a have outlets 10 b on the oil 2 side, and the oil 2 aflowing through the second supply pipe 10 passes through the supplytubes 10 a to be discharged from the outlets 10 b into the oil 2, asshown in FIG. 9. Further, as shown in FIG. 10, communication portions 10c for discharging the oil 2 a flowing through the first supply pipe 7into the sodium acetate 3 are provided for the second supply pipe 10 atpositions that superpose the discharge holes 7 a of the first supplypipe 7 to be surrounded. Note that description of the other members willbe omitted because they are the same as the first embodiment.

Next, description will be made for the heat storage method to the heatstorage unit 1.

Steam passes through the pipe from the factory 60 and is taken into theheat exchanger 5 a. On the other hand, the oil 2 in the heat storagecontainer 1 a is taken into the heat exchanger 5 a via the dischargepipe 6. Then, in the heat exchanger 5 a, heat of the steam is suppliedto the oil 2 that was taken in. At the starting point of heat storage,only the valve 9 b is opened to allow the oil 2 a to be supplied only tothe second supply pipe 10. Therefore, the oil 2 a to which heat wassupplied flows through the second supply pipe 10, passes through thesupply tubes 10 a, and is discharged from the outlets 10 b into the oil2.

When the oil 2 a to which heat was supplied flows through the secondsupply pipe 10 and the supply tubes 10 a, the oil 2 a conducts heat tothe sodium acetate 3 by indirect contact via the second supply pipe 10and the supply tubes 10 a. With this, the sodium acetate 3 graduallychanges from solid to liquid. When the sodium acetate 3 becomes liquid,the valve 9 b is closed and the valve 9 a is opened. This allows the oil2 a to be supplied to the first supply pipe 7. Once the sodium acetate 3becomes liquid, the discharge holes 7 a and the communication portions10 c are not clogged and the oil 2 a can be discharged from thedischarge holes 7 a and the communication portions 10 c. Further, whenthe oil 2 a flows through the first supply pipe 7, heat is conductedfrom the oil 2 a flowing through the surrounding second supply pipe 10.This further increases the temperature and time to store heat in thesodium acetate 3 can be further shortened.

As described above, in this embodiment, in addition to the effect of thesecond embodiment, additional heat is supplied from the second supplypipe 10 to the oil 2b flowing through the first supply pipe 7 becausethe first supply pipe 7 is surrounded by the second supply pipe 10, andheat can be stored even faster by discharging the oil 2 a into thesodium acetate 3. Moreover, areas of the first supply pipe 7 and thesecond supply pipe 10 arranged in the sodium acetate 3 can be madesmaller.

Meanwhile, in this embodiment, the second supply pipe 10 surroundsapproximately the entire first supply pipe 7 in the sodium acetate 3,but it may surround only a part of the first supply pipe 7. Further,similar to the second embodiment, the oil 2 a may be supplied to both ofthe first supply pipe 7 and the second supply pipe 10 after the sodiumacetate 3 changes to liquid. In addition, the pipes may not have thevalves 9 a, 9 b.

(Fourth Embodiment)

Next, description will be made for the heat storage unit according tothe fourth embodiment of the present invention. The heat storage unitaccording to this embodiment is the same as the third embodiment on thepoint that it is provided with two supply pipes and one supply pipesurrounds the other supply pipe but structure of each supply pipe isdifferent. In the following, only the different point will be described.Note that the same reference numerals are applied to the same members asthose of the first to the third embodiments, and their explanation willbe omitted.

As shown in FIG. 11, the heat storage unit 1 according to thisembodiment has two pipes that are a first supply pipe 15 and a secondsupply pipe 16. The first supply pipe 15 and the second supply pipe 16are provided in the upper layer portion of the heat storage container 1a in a penetrated manner, where the housed oil 2 is positioned, and isdetachably connected to the heat exchanger 5 a. Specifically, theconnection port of one supply pipe 11 is detachably connected to theconnection port 51 of the heat exchanger 5 a, and the supply pipe 11branches into the first supply pipe 15 and the second supply pipe 16.

The first supply pipe 15 and the second supply pipe 16 vertically crossthe boundary surface between the oil 2 and the sodium acetate 3 and gointo the sodium acetate 3, and furthermore, are bent in the L-shape andextended horizontally. The first supply pipe 15 is further bent in theL-shape, vertically crosses the boundary surface again, and an outlet 15a for discharging the oil 2 a is provided on the tip of the area bent inthe L-shape. The first supply pipe 15 and the second supply pipe 16 havean internal space, and the oil 2 a to which heat was supplied by theheat exchanger 5 a flows in the internal space. In a portion wheresupply pipes 15, 16 are horizontally extended, a second supply tube 16surrounds the first supply pipe 15.

The portion where the supply pipes 15, 16 are horizontally extended isarranged on the bottom surface of the heat storage container 1 a. Withthis, contact time of the oil 2 a discharged from discharge holes 16 aand the sodium acetate 3 can be made longer, and heat of the oil 2 a canbe sufficiently conducted to the sodium acetate 3. Further, as thesodium acetate 3 changes to liquid, the oil 2 a has a smaller specificgravity than that of the sodium acetate 3 and goes up once it isdischarged from the discharge holes 16 a, so that it becomes difficultto conduct heat to the sodium acetate 3 near the bottom surface of theheat storage container 1 a and a long time is necessary in storing heat.However, by providing the first supply pipes 15, 16 on the bottomsurface, heat can be sufficiently stored in the sodium acetate 3 nearthe bottom surface, and the heat storage time can be shortened.

Further, the discharge holes 16 a for discharging the oil 2 a into thesodium acetate 3 are provided on the second supply pipe 16 in theopposite direction to the bottom surface side of the heat storagecontainer 1 a. With this, the oil 2 a supplied to the supply pipe 11passes through the first supply pipe 15 and is discharged from theoutlet 15 a into the oil 2, and on the other hand, passes through thesecond supply pipe 16 and is discharged from the discharge holes 16 ainto the sodium acetate 3.

Next, description will be made for the heat storage method to the heatstorage unit 1.

Steam passes through the pipe from the factory 60 and is taken into theheat exchanger 5 a. On the other hand, the oil 2 a in the heat storagecontainer 1 a is taken into the heat exchanger 5 a via the dischargepipe 6. Then, in the heat exchanger 5 a, heat of the steam is suppliedto the oil 2 that was taken in. After that, the oil 2 a to which heatwas supplied is supplied to the supply pipe 11, and flows through thefirst supply pipe 15 and the second supply pipe 16. The oil 2 a flowingthrough the first supply pipe 15 is discharged from the outlet 15 a intothe oil 2. Further, oil 2 a flowing through the second supply pipe 16 isdischarged from the discharge holes 16 a into the sodium acetate 3.

Since the sodium acetate 3 is solid at the starting point of heatstorage, it becomes difficult for the oil 2 a to be discharged from thedischarge holes 16 a and the outlets are clogged, and thus the oil 2 acannot flow well through the second supply pipe 16. Then, there is adanger that the temperature of oil 2 a is reduced while they areclogged. On the other hand, since the outlet 15 a of the first supplypipe 15 is provided in the oil 2, the oil 2 a can constantly flowthrough the first supply pipe 15 regardless of the state of the sodiumacetate 3 at the starting point of heat storage, and thehigh-temperature oil 2 a constantly flows in the first supply pipe 15.Therefore, heat is conducted to the oil 2 a in the second supply pipe 16by contacting the first supply pipe 15 in which the high-temperature oil2 a constantly flows, and high-temperature can be maintained withoutreducing temperature. With this, the high-temperature oil 2 a can bedischarged from the discharge holes 16 a to the sodium acetate 3.Furthermore, high-temperature can be also maintained in the secondsupply pipe 16, and heat can be conducted to the sodium acetate 3 nearthe second supply pipe 16 as well.

Meanwhile, in this embodiment, the supply pipes 15, 16 are arranged onthe bottom surface of the heat storage container 1 a, but they may notbe arranged on the bottom surface. In this case, the disposing positionsof the discharge holes 16 a are not limited as described above. In thecase where the supply pipes 15, 16 are not arranged on the bottomsurface, it is preferable that the supply pipes 15, 16 be arranged nearthe bottom surface.

As described above, in this embodiment, since heat is conducted from thesupply pipe 15 to the oil 2 a discharged from the discharge holes 16 a,it is possible to constantly maintain high-temperature and the heatstorage time can be shortened. Further, by arranging the supply pipes onthe bottom surface of the heat storage container 1 a, the contact timeof the discharged oil 2 a and the sodium acetate 3 can be made longer.Then, although the oil 2 a goes up due to light specific gravity and itbecomes difficult to store heat in the sodium acetate 3 in the lowerportion, heat can be stored in the entire sodium acetate 3 by arrangingthe supply pipes on the bottom surface.

Furthermore, as a modified example of this embodiment, the supply pipes15, 16 may be provided parallelly in the lateral direction with the samegap as shown in FIG. 12. By providing the pipes parallelly, it becomespossible to allow the oil 2 a and the supply pipes 15, 16 to directlycontact the sodium acetate 3 over a wider range, and the heat storagetime can be made even shorter. In this case, it is preferable that acorrugated conduction plate 17 (thermal conduction member) be providedso as to join each supply pipe 15, 16.

The conduction plate 17 has a corrugated shape where circular arcs areoppositely joined alternately, the second supply pipes 16 are fittedinto the circular arc portions, they are closely adhered by welding orthe like, and arranged on the bottom surface. With this, the contactarea between the second supply pipe 16 and the conduction plate 17becomes larger and heat quantity to be conducted to the conduction plate17 becomes larger, and heat can be sufficiently conducted to the sodiumacetate 3 between the supply pipes 15, 16. Consequently, the heatstorage time can be made even shorter. It is preferable that theconduction plate 17 be constituted by metal having high thermalconductivity such as copper, aluminum and iron. Note that the conductionplate 17 may be a planar shape instead of the corrugated shape. Inaddition, the supply pipes 15, 16 may be parallelly provided in alongitudinal direction and adjacent supply pipes 15, 16 may not bearranged in the same gap.

Further, as another modified example, as shown in FIG. 13 and FIG. 14,the second supply pipe 16 may cover approximately the entire bottomsurface of the heat storage container 1 a and the first supply pipe 15may be extended in the second supply pipe 16 covering the bottomsurface. By arranging the second supply pipe 16 so as to approximatelycover the bottom surface, heat can be conducted from the entire lowerportion to the sodium acetate 3, and the heat storage time can befurther shortened. Moreover, since the first supply pipe 15 is designedto pass through the entire second supply pipe 16, the oil 2 a in thesecond supply pipe 16 can be maintained at high-temperature. In thiscase, it is preferable that the first supply pipe 15 pass near thedischarge holes 16 a. This makes it possible to maintain the oil 2 a tobe discharged from the discharge holes 16 a at as high-temperature aspossible, and the heat storage time can be shortened.

Furthermore, as another modified example, a separation device 14(separation mechanism) as shown in FIG. 15 may be provided between theoutlet 15 a of the first supply pipe 15 and the discharge pipe 6. Theseparation device 14 is a device for separating the oil 2 and the sodiumacetate 3 when the sodium acetate 3 is mixed into the oil 2 that wastaken in. The separation device 14 has a main body 14 a (separator) thattakes in the oil 2 containing the sodium acetate 3. The oil 2 is filledin the main body 14 a, the oil 2 horizontally taken into the body flowshorizontally in one direction, and then is discharged. Further, thebottom surface of the main body 14 a has a level surface and a tiltsurface, where a hole 14 b for discharging the sodium acetate 3 isprovided in the level surface. Although described later, since thebottom surface has the tilt surface, the sodium acetate 3 to beprecipitated is guided toward the hole 14 b.

When the oil 2 contains the sodium acetate 3, the sodium acetate 3having a larger specific gravity than that of the oil 2 precipitateswhile horizontally flowing in the main body 14 a. The precipitatedsodium acetate 3 is discharged from the hole 14 b. Further, since thebottom surface of the main body 14 a has the tilt surface, the sodiumacetate 3 precipitated on the tilt surface also moves toward the hole 14b in a sliding manner to be discharged from the hole 14 b. By providingthe separation device 14 between the outlet 15 a and the discharge pipe6, the sodium acetate 3 is not contained in the oil 2 a any more. Inaddition, even in the case where the sodium acetate 3 is contained, thesodium acetate 3 can be precipitated and removed, so that a danger offailure or the like caused when the sodium acetate 3 enters the heatexchanger 5 a is eliminated. Note that the separation device 14 may beprovided halfway the discharge pipe 6.

The present invention is described in the above-described preferredembodiments, but the present invention is not limited only to them. Itshould be understood that other various embodiments can be implementedwithout departing from the spirit and scope of the present invention.Furthermore, operations and effects by the constitution of the presentinvention are described in these embodiments, but these operations andeffects are only examples and do not limit the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 An entire schematic view of the heat transportation system of thepresent invention

FIG. 2 A sectional view of the heat storage unit according to the firstembodiment of the present invention

FIG. 3 A modified example of the heat storage unit according to thefirst embodiment

FIG. 4 Another modified example of the heat storage unit according tothe first embodiment

FIG. 5 Another modified example of the heat storage unit according tothe first embodiment

FIG. 6 Another modified example of the heat storage unit according tothe first embodiment

FIG. 7 A sectional view of the heat storage unit according to the secondembodiment of the present invention

FIG. 8 A sectional view of the heat storage unit according to the thirdembodiment of the present invention

FIG. 9 A sectional view on IX-IX line of FIG. 8

FIG. 10 A sectional view on X-X line of FIG. 8

FIG. 11 A sectional view of the heat storage unit according to thefourth embodiment of the present invention

FIG. 12 A modified example of the heat storage unit according to thefourth embodiment and a sectional view on XII-XII line of FIG. 11

FIG. 13 Another modified example of the heat storage unit according tothe fourth embodiment and a sectional view on XIII-XIII line of FIG. 11

FIG. 14 Another modified example of the heat storage unit according tothe fourth embodiment and a sectional view on XIV-XIV line of FIG. 11

FIG. 15 Another modified example of the heat storage unit according tothe fourth embodiment and an enlarged sectional view of a separationdevice

EXPLANATION OF REFERENCE NUMERALS

1 Heat Storage Unit

-   1 a Heat storage container-   2 Oil-   2 a Oil (to which heat is supplied)-   3 Sodium acetate-   4 Supply pipe-   4 a, 4 b Discharge hole-   5 a, 5 b Heat exchanger-   6 Discharge pipe

1. A heat storage unit comprising: a storage container that houses aheat storage body, which stores heat by a state change from solid toliquid, and a heat exchange medium, which exchanges heat by directlycontacting said heat storage body, has a smaller specific gravity thanthat of said heat storage body, and is separated from said heat storagebody; a supply pipe that passes through at least said heat storage bodyhoused in said storage container and supplies said heat exchange mediuminto the storage container; and a discharge pipe that discharges saidheat exchange medium housed in said storage container to the outside ofsaid storage container, wherein said supply pipe crosses a boundarysurface between said heat exchange medium and said heat storage bodyhoused in said storage container, has a plurality of discharge holesthat discharge said supplied heat exchange medium, and at least one ofsaid discharge holes is positioned inside said heat exchange medium. 2.The heat storage unit according to claim 1, wherein said supply pipecrosses vertically with respect to said boundary surface.
 3. The heatstorage unit according to claim 2, wherein said supply pipe is disposedcoaxially around the circumference of an area having said dischargeholes and has a circulation pipe to allow said heat exchange mediumdischarged from said discharge holes to go up in the vertical direction.4. The heat storage unit according to claim 1, wherein in the case wheresaid supply pipe or at least a part of said first supply pipe extends inthe horizontal direction, said discharge holes are provided for an areaextending in the horizontal direction such that the holes are open inthe vertically downward direction.
 5. The heat storage unit according toclaim 1, wherein in said heat storage body, said supply pipe or saidfirst supply pipe has an expanded portion that is in a shape that widenstoward the end and provided with said discharge holes on the bottomsurface.
 6. The heat storage unit according to claim 1, wherein aconnection port of said supply pipe is positioned above a connectionport of said discharge pipe.
 7. The heat storage unit according to claim1, comprising: wave-absorbing plates that are parallelly arranged witheach other along the boundary surface between said heat storage body andsaid heat exchange medium and arranged vertically with respect to saidboundary surface, and prevents agitation on said boundary surface. 8.The heat storage unit according to claim 1, wherein said discharge pipeincludes a separation mechanism that separates said heat storage bodyand said heat exchange medium.
 9. The heat storage unit according toclaim 8, wherein said separation mechanism has a separator for allowingsaid heat exchange medium and said heat storage body, which were takenin, to flow horizontally in one direction and a discharge hole thatdischarges said heat storage body, which is being precipitated, fromsaid separator, and said separator has a shape for guiding saidprecipitated heat storage body toward said discharge hole.
 10. The heatstorage unit according to claim 1, wherein said heat storage body iserythritol.
 11. A heat storage unit comprising: a storage container thathouses a heat storage body, which stores heat by a state change fromsolid to liquid, and a heat exchange medium, which exchanges heat bydirectly contacting said heat storage body, has a smaller specificgravity than that of said heat storage body, and is separated from saidheat storage body; a supply pipe that passes through at least said heatstorage body housed in said storage container and supplies said heatexchange medium into the storage container; and a discharge pipe thatdischarges said heat exchange medium housed in said storage container tothe outside of said storage container, wherein said supply pipeincludes: a first supply pipe having discharge holes that discharge saidsupplied heat exchange medium into said heat storage body; and a secondsupply pipe that crosses the boundary surface between said heat exchangemedium and said heat storage body, which are housed in said storagecontainer, and has an outlet that discharges said supplied heat exchangemedium into the heat exchange medium.
 12. The heat storage unitaccording to claim 11, wherein in said heat storage body, said secondsupply pipe surrounds at least a part of said first supply pipeincluding said discharge holes and has a communicating portion thatguides said discharge holes to said heat exchange medium.
 13. The heatstorage unit according to claim 11, wherein a switching valve forswitching supply and cutoff of said heat exchange medium depending onthe state of said heat storage body is provided severally for said firstand second supply pipes.
 14. The heat storage unit according to claim11, wherein in the case where said supply pipe or at least a part ofsaid first supply pipe extends in the horizontal direction, saiddischarge holes are provided for an area extending in the horizontaldirection such that the holes are open in the vertically downwarddirection.
 15. The heat storage unit according to claim 11, wherein insaid heat storage body, said supply pipe or said first supply pipe hasan expanded portion that is in a shape that widens toward the end andprovided with said discharge holes on the bottom surface.
 16. The heatstorage unit according to claim 11, wherein a connection port of saidsupply pipe is positioned above a connection port of said dischargepipe.
 17. The heat storage unit according to claim 11, whereinwave-absorbing plates that are parallelly arranged with each other alongthe boundary surface between said heat storage body and said heatexchange medium and arranged vertically with respect to said boundarysurface, and prevents agitation on said boundary surface.
 18. The heatstorage unit according to claim 11, wherein said discharge pipe includesa separation mechanism that separates said heat storage body and saidheat exchange medium.
 19. The heat storage unit according to claim 18,wherein said separation mechanism has a separator for allowing said heatexchange medium and said heat storage body, which were taken in, to flowhorizontally in one direction and a discharge hole that discharges saidheat storage body, which is being precipitated, from said separator, andsaid separator has a shape for guiding said precipitated heat storagebody toward said discharge hole.
 20. The heat storage unit according toclaim 11, wherein said heat storage body is erythritol.
 21. A heatstorage unit comprising: a storage container that houses a heat storagebody, which stores heat by a state change from solid to liquid, and aheat exchange medium, which exchanges heat by directly contacting saidheat storage body, has a smaller specific gravity than that of said heatstorage body, and is separated from said heat storage body; a supplypipe that passes through at least said heat storage body housed in saidstorage container and supplies said heat exchange medium into saidstorage container; and a discharge pipe that discharges said heatexchange medium housed in said storage container to the outside of saidstorage container, wherein said supply pipe includes: a first supplypipe having an outlet that discharges said supplied heat exchange mediuminto said heat exchange medium housed in said storage container housedin said storage container; and a second supply pipe that has at least apart of said first supply pipe inside the pipe and has discharge holesthat discharge said supplied heat exchange medium into said heat storagebody.
 22. The heat storage unit according to claim 21, wherein in thecase where said supply pipes are provided parallelly in said heatstorage body, a thermal conduction member for conducting heat of saidsupply pipes is provided.
 23. The heat storage unit according to claim22, wherein at least a part of said supply pipe is provided on thebottom surface of said storage container.
 24. The heat storage unitaccording to claim 21, wherein said second supply pipe is provided onthe bottom surface of said storage container so as to cover said bottomsurface.
 25. The heat storage unit according to claim 21, wherein aconnection port of said supply pipe is positioned above a connectionport of said discharge pipe.
 26. The heat storage unit according toclaim 21, comprising: wave-absorbing plates that are parallelly arrangedwith each other along the boundary surface between said heat storagebody and said heat exchange medium and arranged vertically with respectto said boundary surface, and prevents agitation on said boundarysurface.
 27. The heat storage unit according to claim 21, wherein saiddischarge pipe includes a separation mechanism that separates said heatstorage body and said heat exchange medium.
 28. The heat storage unitaccording to claim 27, wherein said separation mechanism has a separatorfor allowing said heat exchange medium and said heat storage body, whichwere taken in, to flow horizontally in one direction and a dischargehole that discharges said heat storage body, which is beingprecipitated, from said separator, and said separator has a shape forguiding said precipitated heat storage body toward said discharge hole.29. The heat storage unit according to claim 21, wherein said heatstorage body is erythritol.